Multistage well pump



J H PUL INVENjroR J. H. PULS MULTISTAGE WELL PUMP v Filed April 8, 1941 w m m www. www, m u .0. Pf f f iffi.; if f, 1 mf w m. 2 1 um mummw www@ wm. 2 A 211 A r Spt. 22, 1942.

,daf/1M ATTORNEYS Patented Sept. 22, 1942 .UNITED STATI-:s PATENT OFFICE- j d l Y 2.296.821

marismas; WELL rum .101m n. Puis, Los Angeles, cam., mimr, by to The Texas Company.

meme assignments, New York, N..Y.,

a corporation of Delaware Application april s, 1941, serial No. 381,399 s claims. (cl. 1oz- 181) c 'l'his invention relates to well pumps. and more particularly to a multi-stage pump of the working barrel type for pumping fluids such as mixtures of oil and gas. c

'I'lie principal object of this invention is the provision of a pump of this type by means of which a fluid such as a mixture of oil and gas can be pumped upwardly in a well in a plurality of pressure stages and by means of which an improved volumetric eihciency, as well as an improved mechanical eiliciency, will be obtained when pumping gaseous liquids. Other objects are to eliminate iluid pounding and the gas locking of well pumps, and thus increase the production from wells.

There are many oil wells which are capable of 'additional production of the order of from say loto 100 barrels per day each. However, it has heretofore been found impossible to attain this oil production rate due to the fact that the oil contains gas. In the past few years methods and apparatus havel been developed for detecting and analyzing these wells. and various suggestions and methods have been proposed vfor overcoming thedimculties without appreciable suc.- cess. Many types of gas anchors, more or Aless complicated in construction, have been tried in an eiort to remove the gas from the oil 'before it reached the pump in the hole. but in many cases these gas anchors do not provide adequate separation of the gas from the oil. Other problems encountered in the pumping of gaseous liquids have been unsolved and, of these, iiuid pounding and the gas locking of the pumps have perhaps been the most serious.

In accordance with the present invention, a pump has been devised by means of which the rate of production from a well can-be greatly increased, the gas in the oil being compressed in two or more pressure stages so as to assist in the raising of the oil to the surface. In pumping a well at a depth of from say 6000' to 7000', pressures of around 2000# per sq. in. are usually encountered, and at the present time many single stage pumps are being used to frnlsh pres,- sure of this and greater amounts in order to pump oil to the surface from a weil of this depth. Obviously, this manner of raising oil is very inefficient. One'would not think of compressing gas in a compressor to say 2000# in one stage and yet an oil pump is expected to do just that.

In carrying out the invention a pump has been provided having two Ior more stages of compression and in which a vertically reciprocable working barrel is actuated from the vsurface over a stationary plunger havingtwo or more xed pistous. on the' upstroke of the barra the mixture of oil and gas is drawn upwardly through a standing valve into an annular chamber, while at the same time oil and gas previously com- 4 pressed in a similar annular chamberis forced from that chamber into and upwardly through the iixed plunger, and thus upwardly to the sur-A face. On the down-stroke oil and gas previously drawn into the first mentioned chamber is then squeezed into the second chamber through a valved passage in the xed plunger. With this type of pump the working barrel may be reciprocated by means of ordinary sucker rods and the use of flow tubing is therefore rendered unnecessary.

`For a better understanding of the invention reference-may be had to the accompanying draw- 'ing in which:

Fig. 1 is a vertical sectional elevation through the lower portion of a well containing a two stage pump embodying the invention Fig. 2 is a similarview showing aIthree-stage pump, while Fig. 3is a detailed sectional elevation showing a modied form of standing valve containing of the tubing Il, and the vertical reciprocable working barrel 20 disposed in external sliding engagement with the iixed plunger- The barrel 20 can be reciprocated from the surface by any lsuitable means, such as a string of sucker rods 22, connected to the upper end of the working barrel by means of a suitable bonnet which allows the fluid to pass upwardly from the barrel into the interior ofthe tubing I4.

I'he stationary plunger I6 comprises a tubular member to which the reference character I6 has been applied and a pair of pistons 26 and 28 of va diameter such as to have a sliding iit within the working barrel 20. The working barrel is provided near its mid-point with an annular ring 30 formed integral with or attached to the inner surface of the barrel and having an internal diameter such that it will have sliding engagement with the tubular portion of the plunger I6.

. It will thus be seen that the annular plunger or ring 30 in the working barrel divides the space between two fixed plungem ze and za inw the twn chambers 32 and 24. The tubular portions of fthe fixed plunger II is provided with sets of openings or ports It and 34' connecting the interior'of the iixed plunger lto the two chambers I2 and 24, respectively. The fixed plunger is also provided beyond and below the ports 34 and 34 with suitable valve seats with which valves 4l and 42, 44 and 4l, are adapted to cooperate. The lowermost valve 4l can be considered the equivalent of the ordinary standing valve, and` the purpose of the other valves will be brought out subsequently.

In operation, it will be noted that `on the.

.downstroke of the working barrel 24 the chamber 32 is becoming smaller while the chamber 34 is Abecoming larger, and a mixture of liquid, such l as oil and gas previously trapped in the chamber n, win be forced into the ports n, mm the plunger I4, upwardly past the valves 42 and 4.4 and through ports 34 into chamber I4. After the pump has been in operation for a few strokes a certain amount of gas will remain compressed in 20 and into and upwardly through the tubing I4.-

At thesame time, fresh oil and gas will be drawn' past the valve 40 and through the ports 20 into' the chamber 32 to fill this chamber. If the pump is properly designed with the proper minimum in the clearance space the oil can be forced upwardly past the valve 46 in a very eillcient manner at the pressure of 2000# per sq. in. and higher. It is believed clear vthat on the up-stroke of the working barrel -the valve 40.will beopen while the valve 42 will remain closed. same stroke the valve 44 will remain closed while the valve 46 will open'as soon as the pressure within the chamber 34 has reached the amount of pressure in the oilcolumn in the well tubing above that valve. On .the down-stroke the valve 40 will remain closed while the valves 42 and 44 will open to allow passage of the fluid from the chamber 32 to thechamber 34, the valve 44 remaining closed throughout thisvstroke.

Obviously, the operation can be carired through more than two compression stages, and in Fig. 2 the 3-stage working barrel pump is very similar to the' pump shown in Fig. 1, except that the ilxed plunger 50 is provided with an upper extension 52 above the'xed pistons 54 and 54 and the working barrel 58 is provided with a lower internal ring or plunger 60 and an upper plunger 62. The fixed plunger is provided with 3 sets of ports 64, 60 and- 08 communicating wit sides of the ports 64, 66 and 6l are respectively the valves 16 and 18, 80 and 22, and 44 and I4.

It will be noted that the operation of the threestage pump' is very similar to that described with reference to' the pump shown in Fig. l. On the up-stroke of the working barrel a mixture of oil and gas is drawn from the well into the chamber 10, while oil .and gas is at the same time forced gas mixture is drawn from the well the entire,y

andassi x oil and gas is compressed in the chamber 1l and is forced past the valves Il and I4 into the chamber 12. The oil and gas mixture previously compressed into the chamber 14 is further compressed until the pressure reaches the pressure of the oil column above valve I8, at which time that valve opens allowing the mixture from chamber 14 to pass upwardly through the tubing string to the surface. Again, as was the case with the twostage pump, if the pumpv is carefully designed so that there will not be undue clearance in the various chambers, the'mixture of oil and gas canbe taken at well pressure'and compressed in substantially equal stages until it leaves the chamber 14 at pressure'of say 2000# or greater.

In some instances it may be found desirable to allow some of the fluid to bleed back into the well past the standing valveln order to limit the maximum .pressure to be developed above the standing valve 44 or 1I. In Fig. 3 a combined standing and relief valve is illustrated, this valve being'seated in a suitable pump lock I8. The valve comprises a vertically movable hollow member 9| having side guide wings l2 and openings at the `top and bottom. The ball valve 04 is pressed against the inner top edge of the valve 90 by means of a suitable compression sprlng When the oii or oilvalve ll will raise allowing the fluid to pass around the valve. When the valve 90 is closed, that is, in its lower seated position, in case the pressure above the valve should exceed -a predetermined amount, the valve 94 will open thus bleeding some of the iluid back into the well.

Obviously, many modications and variations of the invention as hereinbefore set forth may be three closed chambers 1li, 12 and 14. At-the upper and lower from the chamber 12 up into the chamber 14, the

valves 16, 82 and being open while the valves 18, I0 and are closed. On the-,down-stroke the 75 made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

l. A multi-stage 'well pump comprising a fixed tubular plunger having a pair of pistons secured in spaced relation along a central tube, means for securing the lower end of said tube in the tubing or casing of the well so that liquid to be produced .will now upwardly into the tube, a vertically reciprocable barrel movable on said pistons in telescoping relation to said fixed plunger, a ring member secured to the inner surface of said barrel between said .pistons and forming with said pistons an upper and a lower chamber, said tube being providd with ports connecting the interior of the tube with each of said chambers and upwardly opening check valves disposed in said tube above and below each of said ports, the arrangement being such that on the upstroke of said barrel iluid will be drawn from the well into said lower chamber and nuid in the upper chamber will be forced into the tubular plunger and upwardly in the tubing, while on the down stroke fluid in the lower chamber will -be forced through a portion of said tubular plunger into the upper chamber.

2. A multi-stage well pump comprising a stationary tubular rplunger having a pair of enlarged pistons disposed in spaced relation along a concentric tube open at its upper and lower ends, means for securing the lower end of said tu-be in the tubing or easing of the well, a vertically movable working barrel surrounding said plunger and having friction engagement with said pistons, said barrel being provided 'near its midpointwith an inner-movable plunger member disposed between said pistons and forming with said pistons a low pressure and high pressure chamber, a pair of upwardly opening check valves in said tubes opposite saidlow pressure chamber, a second pair of upwardly opening check valves in said tube opposite said high pressure chamber Ports disposed between each pair of valves connecting the interior of said tubes with said low and high pressure chambers and means for reciprocating said barrel, so that on the up stroke of said barrel fluid lwill lbe drawn from the well into the low pressure chamber and iiuid previously compressed in said high pressure chamber will be forced into the tubular plunger and upwardly in the tubing. while on the down stroke fluid in the low pressure chamber will be forced through a portion of said tubular plunger into the high pressure chamber.

3. A multi-stage well pump comprising a fixed tubular plunger having a .pair of pistons secured in spaced relation along a central tube, means for securing the lower end of said tube in the tubing or casing of the well so that liquid to be produced iiow upwardly into the tube, a vertically reciprocable .barrel movable on said pistons in telescoping relation to said fixed plunger, a pair of annular upper and lower projections extending inwardly from said barrel into-sliding engagement with said tube, and forming with said pistons low, medium and high pressure chambers, ports connecting the interior of said tube with each of said chambers and upwardly opening check valves disposed above and below each of said ports, the arrangement being such that on the up stroke of said barrel iluid from the well below the pump will be drawn into the low pressure chamber and fluid from. the medium pressure chamber will be forced through a portion of said tubular plunger into the high pressure chamber, while on the down stroke of the barrel the fluid will be forced from the low pressure chamber through another portion of the plunger into the medium pressure chamber and fluid previously compressed in the high pressure chamber will be forced into the tubular plunger 20 and upwardly through the well tubing.

JOHN H. PULS. 

